OICC Press International Journal of Nano Dimension 2228-5059 17 2 2026 04 10 Antibacterial Activity of Nisin Incorporated into Chitosan/Alginate Nanoparticles as a Biopreservator Agent in Sausage 10.57647/j.ijnd.2026.1702.02 EN Homa Khorasani Department of Microbiology, Ke.C., Islamic Azad University, Kerman, Iran Seyed Mansour Meybodi Department of Microbiology, To.C., Islamic Azad University, Tonekabon, Iran Nadia Kazemipour Department of Microbiology, Ke.C., Islamic Azad University, Kerman, Iran Sayed Mohammad Reza Khoshroo Department of Microbiology, Ke.C., Islamic Azad University, Kerman, Iran Mohammad Mehdi Motaghi Department of Microbiology, Ke.C., Islamic Azad University, Kerman, Iran Journal Article 2026 04 10  This study investigates the antimicrobial effects of nisin extracted from Lactococcus lactis and the enhancement of its antimicrobial effect by incorporation into chitosan/alginate nanoparticles. Native strains of Lactococcus lactis were isolated from milk samples and the presence of the nisin gene was confirmed using polymerase chain reaction (PCR). Nisin concentration was determined using high-performance liquid chromatography (HPLC). The results showed that out of ten isolated strains, four strains (L1, L3, L8 and L9) showed genetic similarity to Lactococcus lactis with percentages of 82.45%, 79.87%, 93.33% and 79.87%, respectively. The optimal growth conditions for the most effective strain were determined at 30°C and pH 7 with an optical density of 5.51 at 600 nm. Nisin extract showed a significant inhibitory zone of 19 mm against Bacillus cereus, while nisin-containing nanoparticles showed an enhanced inhibitory effect of 20 mm. Furthermore, the results showed that the combination of nisin-containing nanoparticles significantly improved the antimicrobial activity compared to nisin alone. This study showed that nisin incorporated into nanoparticles effectively retained its antimicrobial properties, indicating its potential as a valuable model for biopreservation of food. These findings emphasize the importance of using natural antimicrobials in food preservation.